At 7:55 AM PDT this Monday, the Scaled Composites SpaceShipTwo (SST) attained a peak velocity of Mach 1.2 at an altitude of 55,000 feet (nearly 17 km) above the Mohave Desert with a 16-second burn of its 30-ton (27-tonne) thrust rocket engine. Piloted by Mark Stucky and Mike Alsbury with an assist from Dave Mackay in the mother bird White Knight Two, this flight marks a stepping-off point for commercial manned spaceflight.

Scaled Composites (SC) first flew SpaceShipOne into space on June 21, 2004, thereby winning the Ansari X Prize. Now, nearly nine years later, SC and Virgin Galactic have completed design and construction of the SpaceShipTwo, intended to launch six passengers and two pilots into space.

This lengthy design and testing effort culminated on April 12 in a "cold flow" test flight. Cold flow testing checks all components in the propulsion system, with only an ignition source standing between a glide test and a powered test. Today they lit that fire.

"Today was the most significant day in the program," Branson told NBC News afterward. "I think that for those people who have been good enough to stick with us for the last eight years, who signed up early on, their time to become astronauts is very soon now. ... We'll soon be able to make their dreams come true."

Launch Timeline

6:50 AM PDT – The Proteus chase plane took off to get into position to monitor the test flight. Proteus is a twin-turbofan, high-altitude aircraft designed to reach altitudes above 60,000 ft (18,288 meters) and remain on station up to 14 hours;

6:58 AM PDT – An unknown airplane attempted to land at the Mohave Air and Space Port, apparently not having checked the FAA notices to airmen;